


Adult Human Incubator Wanted

by SpireGod349



Category: Invader Zim
Genre: F/M, Other, Oviposition, Tentacle Dick, Tentacles, Vaginal Sex, Xenophilia
Language: English
Status: Completed
Published: 2018-12-25
Updated: 2018-12-25
Packaged: 2019-09-27 04:08:04
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 6,560
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17155022
Author URL: https://archiveofourown.org/users/SpireGod349/pseuds/SpireGod349
Summary: Zim is in your neighborhood searching for HOT ADULT HUMANS WHO WOULD LIKE TO FUCK and you have wanted to fuck aliens all your life. Epic sex ensues. Also there is oviposition involved, hurray. One-shot.





	Adult Human Incubator Wanted

**Author's Note:**

> Reader is a college student (18+), typically submissive, and has breasts and a uterus/vagina. Bear with me for the goofier aspects of this story, it's meant to be tonally adjacent to the show and I also couldn't come up with a premise that was both realistic and short on exposition AND would work all the kinks in. Is this how the people who write porn screenplays feel?
> 
> I wrote the bulk of this in two nights so if the pacing is weird or there are errors I am so sorry.

  

> Reply: irkeninvadergreatzim@braigslist.org
> 
> **Looking For Human For Breeding Study**
> 
> Seeking a temporary human test subject to study human reproduction, namely the ability of humans to incubate the eggs of extraterrestrial lifeforms. I am totally also a human.
> 
> Potential candidate should be a fertile human adult in good health. Session will take no longer than four hours, and scheduling is flexible. Any potential offspring will be terminated at the end of the study. Study may also terminate at any time at participant's behest. I can compensate in cash and food/beverages.
> 
> _Location: Fair Springs, Dayton_

You squinted at your laptop screen. Were you reading this properly? You just happened to be passing through the area, crashing on a friend's couch for a week before fall semester started up again, and scrolling through Braigslist on a whim, as you did sometimes when you were bored. And here, right in front of your eyes, seemed to be a genuine solicitation from an alien to fuck. In front of you, the alien fucker.

Well, it was probably just another person RP'ing as an alien, or worse, someone with malicious intent. The way the ad was worded, though, made it seem far more likely the former than the latter, in which case you'd just have a conversation with somebody who shared a similar enthusiasm for alien sex. A conversation you'd had a few times before. No biggie. And if it was the latter, well... You'd used pepper spray before. No biggie there either.

You shot "irkeninvadergreatzim@braigslist.org" a message, and received a near instantaneous reply, which was surprising. The instructions led to a relatively normal-looking house in your phone's map app, and a relatively short walking distance from where you were currently staying, which was surprising, too. _Well, maybe it's written in the stars,_  you thought to yourself, before texting your friend-host where you were going and when and how long and why.

They texted back, with joking seriousness, then with more open concern. To assuage them, you promised to bring the baseball bat along with the pepper spray. They remained unconvinced, so you promised to be back by a certain time, and when they stressed how they were responsible for your well-being during your stay, you reluctantly downloaded an app that would cause your phone to, after a set amount of time, first send out an emergency message with its current location and then detonate.

Your friend reluctantly allowed you to go, but not before cautioning you that the app would "seriously, actually explode" your phone, and that in the case of it going off, to watch out for shrapnel. Thus, armed with pepper spray, a baseball bat, a ticking time bomb of a phone, and an unextinguishable desire to fuck extraterrestrials, you found yourself trekking uphill on a rather warm Ohio summer day.

* * *

 

Once you reached the house, you found that you couldn't stop your heart from thudding loudly, even after sitting down and taking a rest. Figuring it was now or never, rang the doorbell. Then you gulped, and steeled yourself for the worst.

The door swung open and what seemed to be a robotic stuffed green dog was standing there in front of you. You stared at it, uncomprehending, before it was pushed aside by a tiny green man with... Pink eyes and insectlike antennae. Holy shit. "I- I'm here about the uh. The Braigslist ad," you said, trying to make your voice sound not like a squeak.

"EXCELLENT!" The alien pumped both hands into the air. "Wonderful. Now if you'll--"

"Are you an actual alien?" The words tumbled out of your mouth. They-- It-- The alien stared at you, as much as one could stare with those pupilless pink eyes.

"What are you talking about? I am absolutely a human," the alien huffed, taking a step back and crossing their arms.

Confounded, you stood speechless for a moment. "Well that's uh, too bad, because I was only interested in, uh, having sex with an extraterrestrial," you said.

"Sex? Mating?!" the tiny green man screeched. "Where was there mating in my internet ad?!"

"W-well, you said something about incubating eggs, and uh, human reproduction, so I thought--"

"Ohh he's gonna be layin' eeeegggs!" The robot dog, which was lying in the corner in a heap, suddenly spoke up in a metallic, high-pitched whine.

"I will not be laying eggs, GIR," the alien spat. At this point you were fairly convinced that was actually an alien. He turned back to you. "I have pre-prepared a sample of frozen eggs and planned to insert them via catheter. There is no..." The alien shuddered. "No INTERCOURSE scheduled for today."

"That's fine, I mean--," you said, stepping forward onto the "Welcome" mat in front of the door. "It-- It doesn't have to be sex. I'm fine with getting alien eggs stuck in me through a tube. I just wanted to know if you were, like, y'know. Actually an alien. For real. And not just some really short guy in a costume."

The alien sighed and before you could blink, a silvery something flashed in front of your face. Then you blinked, and it appeared to be an insectlike mechanical leg, extending out from a pod on the alien's back. "I am Irken Invader Zim of the Irken Empire, tasked with conquering your planet, Earth, in the name of the Almighty Tallest," Zim said as he retracted the mechanical leg slowly. "But as of recent I tire of conquest, and now occupy myself with mere study of your species' biology and cultural norms. Happy?"

"Sure," you said, shrugging. Holy shit. A real alien. A real alien about to put his real alien eggs in you. You weren't too keen about normal human pregnancy, but being pumped full of an alien's genetic material? Hot. And it was about to happen. You got so wrapped up in your excitement that you didn't notice Zim staring up at you quietly.

"What's with the baseball bat?" he asked.

"Oh, uh... I was just... Playing some baseball," you said, suddenly aware that you were not dressed for baseball. You paused. "Sometimes humans put up ads on the internet to find other humans they can hurt," you explained. "Hence... The bat."

The alien nodded sagely, as if already wise to the evil ways of mankind. "Well, I mean you no harm. Come in."

* * *

 

Zim led you through his strangely laid out bathroom down into an elevator, which opened out into a walkway that then led into a small lab. In the middle of the lab was a reclining, padded table.

"Disrobe," Zim ordered, pointing at the medical gown hanging on the side of the table. "You can wash and clean yourself over there," he added, pointing at a sink in the corner outfitted with several hand towels. "I'm going to go fetch the eggs." After he left, you did as he said, removing every last article of clothing from your body and wiping your nether regions down. Your underwear was disgustingly slick with wetness from your excitement, and you were torn between wiping off your sticky thighs or letting them stay and tempt Zim. Then Zim came back.

You instinctively hid yourself before remembering what you were here for. Still, it was a bit awkward taking your hands off your crotch. "Put the gown on," Zim said, not looking at you. Briskly professional, he was wearing a cute little white lab coat, and his hands, now coated in blue gloves instead of black, clutched what appeared to be an electronic clipboard in one hand, a small plastic box in the other. He set down the clipboard on a nearby stand and took a small syringe and some plastic tubing out of the box. "Lie on the table and spread your legs."

You did so, and noticed Zim turning red in the face as he snaked the plastic tubing up through your pussy into your womb. "I'm just going to... Stick these in," he said, connecting the syringe to the tubing. And he did. You shivered at the cold fluid deep inside your body.

"Now what?" you said.

"Now we wait," Zim said, removing the tubing from your nethers. "And you can close your legs," he added.

Maybe it was just your imagination, but you could feel the eggs swelling up inside you already, soaking up moisture from your womb, and your tits and pussy beginning to engorge from the stimulation. You were already wet as hell by the time you'd laid down, and this wasn't helping. You clapped your knees shut, trying to tamp down on the feeling, and gingerly squeezed one of your breasts. Yep, that was tender, and you moaned involuntarily.

You looked over at Zim, who was watching you, gripping his e-clipboard stiffly, transfixed while in between one task and another. And you didn't mean to glance at his crotch, but you did anyway, and was that a... A  _bulge_ forming there?

"Hey Zim," you said, "I don't know anything about, uh, Irken anatomy, but it looks like--"

"Silence!" Zim snapped, his antennae sticking straight up.

"I was just going to say it looks like you've got something stuck in your pants."

"That is none of your business," Zim hissed, moving his clipboard lower to hide his crotch. "You just happen to.. Your reproductive organs just happen to produce a signaling pheromone that is most attractive to Irkens."

"You guys can smell?" You didn't see any nostrils on Zim.

"We absorb scents through our skin," Zim said, trying his best to combat an impressive blush.

"I see," you said, yourself struggling to ignore the pulsing feeling in your abdomen. "Well," you said before you could stop yourself, "Why don't you come over here and get a better whiff?"

Zim stood there stiffly for what felt like eternity. You thought the experiment was going to end right then. Thankfully, he blushed redder and, scribbling something down on his clipboard, walked over to where you were lying.

Zim got down to eye level with your pussy, staring at its folds inquisitively. "May I touch?" he asked.

"Of course!" you said. Zim traced the outline of your labia gently with a fingertip.

You noticed something pink and purple peeking out of the top of his pants. "It's thoroughly wettened," he commented, oblivious to your stare. "Is that normal?"

"Your dick is showing, is THAT normal?" you fired back, embarrassed.

"My what--" Zim looked down, aghast, and yelped. The clipboard clattered to the floor as he hurriedly pulled his lab coat in front of his pants. You couldn't stifle a laugh. "What!" Zim snapped.

"Are you suuuure you don't want some of this?" You gestured downwards at your body. "And I can get up, right?"

"I-I don't see why you'd have to stay supine," Zim stammered, ignoring your first question.

"Good," you said, swinging your legs over the side of the table. "Because it's getting kinda hot in here, don't you think?" With that, you began to untie the medical gown.

Zim looked down and hurriedly muttered "Increased-- perceptual-- body-- temperature--" into his clipboard, but made no movement to stop you. So the gown fell in an elegant swoop down to the floor, puddling around your feet.

"Would you look at that," you murmured. "My tits are bigger." You reached one hand down to your crotch. "My clit feels swollen, too..."

You had no idea what was making you so brazen all of a sudden. Normally you were always the one on the bottom, the one receiving, and usually just waiting for the other person to initiate. And you  _were_ planning to take it this time too, it was just.... Your partner was just being so... So shy. Your hand rubbed in a familiar circular motion as you tried not to imagine what Zim would look like with his pants off, and you shook as you stood upright.

In your peripheral vision, you caught Zim sneaking peeks at you. "I don't mind if you look, you know," you said.

"I didn't need your permission," Zim snapped, before clearing his throat. "Let me see if, um. If your body temperature has indeed risen." He pulled out a thermometer from one of the cabinets lining the lab and skittered over to you. "Crouch down and I'll put this in your mouth."

You did as you were told, but as Zim made motion to put the thermometer into your mouth, you took his gloved hand and guided his thumb inside instead, then closed your eyes and sucked. His fingers were sharp at the tips, and surprisingly warm. As you stroked the base of his thumb with your tongue, you opened your eyes lazily to a nonresponsive Zim.

You took the alien's thumb out of your mouth. "You're-- You're not into it. Sorry. I'll stop," you said. "I just. I did really want to fuck an alien. And you seem pretty excited yourself. But you did say you didn't want to have sex. So I'll stop."

"I am perfectly neutral to the concept of sexual intercourse." Zim said, peevishly. "I just-- I was not planning on it, nor intending to advertise for it. I also didn't know what kind of human I would be getting. Nor have I had a sexual encounter with one of your kind before." He paused. "Well, this is all happening--"

"If you don't want to do it I'll stop," you interjected.

"No, you may continue," Zim said. "I already know that intercourse will not interfere with the experiment. And your anatomy does seem compatible, after all." You stared intently, signaling him to continue. He sighed and pulled down his pants, unveiling a thick, wet, shiny, purple-red tentacle, segmented like his tongue. In fact, it looked just like a thicker, smoother version of his tongue. "This.... Is my external sexual organ."

"You have others?"

"Well--" Zim began retracting the tentacle into his body, and indicated his crotch with his hands. "All Irkens are equipped with vestigial internal and external sexual organs. We also have a waste disposal orifice and an oral orifice--" He pointed at his mouth-- "which are occasionally used for intercourse. Now, seeing as  _your_ sex organ is primarily internal, I figured that--"

You flopped down on the table. "Zim, I need that thing in me right now. We can talk about organs and stuff later."

"Very well," Zim said. "Allow me to get situated." You watched, saucer-eyed, as he pulled on and stroked his dick (it was basically a tentacle dick) and it slithered out of him, getting bigger and bigger. As thick as a soda can-- No, thicker-- And it must be over a foot in length at this point.

 _Can I really take that?_  you thought to yourself. But you knew, regardless of the actual answer, that you were going to try to stuff all of it inside anyway.

"You should prepare as well," Zim said, snapping you out of your reverie. Obediently, you began stroking your clit. It was noticeably swollen and sensitive, about four times its normal size, and slick with pussy fluid. Merely touching it with the pad of your finger felt irresistibly good, and you shuddered as you rubbed it back and forth. Did it usually get this huge? You hadn't even had anything in you yet. Well, besides the eggs. You pressed down on your belly, right above your womb, and you could feel them roiling, growing in size, pushing on the rest of your organs and doubtlessly secreting some kind of alien aphrodisiac. Wait-- That was it.

"Zim," you said. "Here's something for your experiment. I think these eggs are making me hornier."

"Horny as in sexually aroused," Zim commented, his eyes closed.

"No, horny as in making me grow horns," you said, sarcastically. Zim opened his eyes and furrowed his brows at you in confusion. You sighed. "I was joking. I think they're... I dunno. They're doing something down there. Making me all hot and bothered."

"The outer layer of the egg  _does_ secrete a hormone-infused mucus," Zim mused. "Perhaps you are having a localized immune response--"

"I'm getting a fever in my pussy?"

"'Pussy' as in internal sexual organ? I could say it's something like a fever." Zim clambered onto the table, lab coat still on. He leaned over you, resting his weight on one arm, stroking his cock with the other.

"Is that going to affect the experiment results?"

"Probably," Zim said. He balanced the tip of his tentacle dick in your opening. "Not much we can do about that now, eh?"

You laughed. "Steady, now," Zim said, as your body shook the bed. "Wait, I have a better idea." The silvery legs you had seen earlier shot out of his back-pod, four of them, hitting the floor with a sharp *tack!* Zim rose up on them, his own legs dangling free, as he prepared to thrust deep inside. You instinctively grabbed his arms to steady him, and he flinched.

"Sorry," you squeaked, and let go.

"It's fine," the alien said huffily. "Do you mind if I--" Zim gestured towards your hips. "Mind if I hold on?"

"Sure," you said, and blushed. Zim removed his gloves, and his pointed fingers, which were green all the way down to the tips, sank into your flesh. "Ow."

Zim adjusted his grip. "Sorry." He seemed unable to fully look down at you. "Are you still... Servicing yourself?"

"I had to stop because it felt too good," you mumbled. "Hurry up," you added.

"Quit ordering me around, human," Zim said, and began sinking his cock inside.

The mere sensation of a hot, hard,  _anything_ against your walls made you already want to cum. Never mind that the thin tip of the alien's dick was slimmer than a cigar. It widened quickly, though, and you lifted the hand you weren't using to touch yourself. "Can I feel?"

"Yes," Zim replied, his own face similarly screwed up in pleasure. "Your sex organ is so... Warm. It's overwhelming."

"Yours too," you said. You could hardly hear anything over the intense feeling in your pussy. "Go-- Go faster. If you keep going this slow I might cum before you even get it all in."

"That aroused, hm." Zim smirked, but complied. "And by 'cum' I assume you mean orgasm."

"Yes, and you might be able to pound me a second time, but I can't guarantee it."

"Understood," Zim said, and slid his dick in until your opening was propped open two inches wide. You yipped, surprised by the thickness, and tightened your hand around the root of Zim's dick.

"N-Not that fast yet," you said, struggling to sit up for a better view of the action. You could feel the alien's dick looping over itself inside, the tip having reached your cervix and now curved back around. Zim sensed your agitation and moved his hips backwards, giving your pussy opening some slack. You noted that there was still at least 6 inches of cock left in between Zim's body and yours, most of it in your grasp. "Here--" You began stroking the exposed shaft with your hand, trying to imitate the rhythm Zim was doing earlier. Zim gasped and trembled, nearly losing his balance and falling on top of you, but caught himself quickly.

"It's OK," you reassured him. "You can lie on me. Actually, if you're OK with it, I would prefer that."

Zim looked at you, his mouth twisted up. "I don't want to catch... Human germs."

"You've got your dick halfway inside me and you're worried about _germs_?"

"Yes," Zim said, crossly, and moaned slightly as you continued to stroke his cock. "I plan to thoroughly sanitize my sex organs afterwards."

You paused. "In that case... You wouldn't mind if I put this inside...?" You began sneaking your hand upwards, towards the opening his tentacle of a dick was coming from.

"That is fine," Zim said. "I said it's fine," he repeated, noticing the disbelief on your face.

"Well, okay," you said, and continued stroking, slowly inching closer to his body. You gazed at his face intently, trying to gauge how close he was to snapping and-- Begging? This alien seemed too haughty to beg. Snarling at you? Both of those outcomes were super cute. And so you continued to tease Zim with your restraint, hoping to provoke some reaction.

Indeed, soon enough, he piped up-- "Well? Are you going to do it?"

"Gimme a second, Zim," you cooed. "How badly do you want me to?"

"Enough," Zim barked. You noticed his face turning red again. He grabbed your hand and put it firmly down on the table, then grabbed your thighs and pushed them backwards towards you. "This position makes entry easier, yes? Focus on pleasuring yourself. It will loosen up your sphincter and make things quick. I would like to be done with this as soon as possible."

"Huh?! Hey, if you want to stop, we should--"

"I said I would like to be _finished as soon as possible,_ " Zim reiterated, turning even redder, in the middle of a halfhearted thrust. "I have no intention of abandoning this venture halfway through."

"Oh, so you like my pussy, then." You couldn't resist teasing him further. "Which way would you _like_  to probe me? You know-- How do you wish you could fuck me?"

"I wish that you would be quiet," Zim grumbled.

"Make me be." Zim opened his mouth, but nothing came out. "I'm serious, though. Do whatever you want to my body. I'm ready for some serious alien lovin'. And if I don't like whatever you decide to do, I'll let you know."

"...As you wish!" Zim leaned back, pulling the rest of his dick out. Before you could protest, pink segmented tentacles shot out of Zim's back-pod, these looking more mechanical and less organic. The air whooshed out of your lungs as the tentacles knocked you down and squeezed you, stringing your thighs to the table, buckling you down by the waist and armpits, and immobilizing your wrists. "Worry not about clitoral stimulation. I have something to handle that." As he spoke, a strange, small suction-cup-looking-thing emerged from his back-pod, connected back to him by a thin wire.

"How do you store all of that in the--- AAAH!" You shrieked as the suction cup on your clit began vibrating. "Zim-- That's so intense! Nnh! It feels so--"

Zim pretended to ignore your cries. "This feature of human anatomy, the 'clitoris,' is remarkably analogous to a feature that all Irkens possess, attributed to the internal sexual organs." Your body shook and quaked against the tentacles holding it, and you couldn't control the noises coming out of your mouth. Zim blazed forwards anyway. "It seems that the human version of this feature is much more sensitive than the Irken one. Perhaps it makes sense, considering that the clitoris is supposed to be the--"

"ZIM!" you hollered. "Zim-- Aanh!-- Mmnn-- Zim, stop giving me biology lessons and just-- Stick your dick back in me already!" Zim kneeled down, returning his knees to the table and his silver mechanical legs to his back-pod. Then he stretched his member to full length and let it flop onto your belly with a loud smack. "Ow!"

He began rubbing it against your skin, the heat and smell and wetness sinking into your body, driving you crazier every second. He glanced at you. "How badly do you want me to?"

He KNEW this was driving you wild. He had to. There's no way he would pull out the whole thing like that and stick it in your face unless he knew. And on top of that, here he was, forcing you to beg with your own words. "Aaahh... Zim... Please...." Good thing you had no shame.

"Go on... Please what?" Zim looked back to his cock, which he continued to massage into your flesh.

Your legs jerked back and forth. "Please... Ahh! I can't think with this vibrator on... Nnh... Please, my pussy is ready... I want to be pumped full of your alien cum! Please fuck my tight hole-- as, as hard as you want! Squirt your--"

"You assume I ejaculate," Zim said, perplexed.

"I don't care! It's okay if you don't, I just need that dick inside RIGHT NOW or I'll--" You did indeed feel close to orgasm. But was Zim lowering the vibrator intensity? You thought for a second. Oh God, he was. "Zim, pleeeEEEaaaAAAAAaaase..... I'll do anything you want...."

"Heh! Don't make promises you can't physically fulfill."

"But I wanna be your cumdoll, Zim," you whined, not thinking about the words you were saying. "I wanna-- Mmh. I want you to fuck me 'til I'm raw. Please? You can use my holes all you want. Um. You can call me a disgusting human or something. If that's what you're into." Zim stared at you, indecisive. "I just--" You squirmed against the tentacles, whose grip was firm as ever.

"Is there a way for you to... To stop looking at me for a while?" Zim said this so abruptly that you almost didn't understand it. "I do enjoy being looked at, in general. But the way you're doing it is so.. Intense. It gives me the shudders."

"Well, yeah, of course, Zim," you blurted out. "I'll just close my eyes." And you did.

"Good. Keep them that way." Zim peeled his still-turgid cock off your skin, and you heard a bottle squirting noise in the background. "Lubricant," Zim explained, as if reading your mind. Then some stroking sounds. "Get ready."

"I'm always ready," you said. This was a lie, as the moment Zim turned the vibrator back to full intensity, you screamed out his name.

"Are you-- I haven't even put it in yet," Zim said, exasperated.

"Zim-- Zim-- Hurry! Please! Aah! I can't take it much longer!" You convulsed in the grasp of the tentacles, your eyes still squeezed shut.

"Hold still," Zim groaned, and grabbed your hips. You relished the sensation of his warm, firm hands on your skin, this small intimacy, as he shoved his cock back in.

This time you were relaxed enough, and your insides stretched to accommodate without complaint. The feeling was overpowering, and your breaths became fast and shallow. "Zim-- Ahh-- Hh-- Zim, it feels so good..! Fuck-- You're filling me up so much--"

"It's, not even, all the way in," Zim panted. His breathing had quickened too. Zim pulled his cock out forcefully, then pushed it back in, this time deeper. You felt your tits bounce back from the force.

"How far in are you?" you stammered.

"Almost there," Zim said, pulling your hips towards him, burying himself deeper inside you. You cried out, pussy opening stretched to its limits once more. Zim began to build up a rhythm of fucking you, his hips slapping against the underside of your thighs.

"More," you gasped. Zim's next thrust sank deeper into you, and you heard a shrill cry emerge from the back of your throat. "More," you gasped again. With your eyes shut, all of your attention was focused on the intense pressure pushing outward against your walls, and the persistent thrumming feeling on your clit, and the sensation of being tossed back and forth by Zim's momentum. "Mmh-- I think I might--"

You tilted your hips, angling for a deep spot in the back. Zim hit it, and a bright stab of pleasure exploded across your mind. "AAAH! Zim! Aah-- Zim-- Yes, there--" He pulled out and then hit the spot again, and the stab turned into an ache-- "Aaah!! Yes-- Nhh--" You could hardly breathe-- "Keep hitting that back there-- Oh God, _yes_ \--"

Zim continued to hammer you, and the delicious sensation built up inside like a dam. Your back arched and your whole body trembled, as you were suddenly aware that you were about to overflow for real. "Keep on-- More-- Please-- I'm gonna-- I'm gonna--"

"Cum" was extinguished by the long, ragged scream that poured out from your lungs. Zim kept going, adding spurts of fuel to the raging fire, as your toes curled and uncurled, muscles jerked and faltered, whole body spasming with bliss. All too soon it was over, and you went limp.

Zim stopped. Then he released you from your tentacle bonds, dropped off the table, and pattered over to the other side of the room, turned on what sounded like a faucet, and returned to your side.

"Drink," he said, nudging your face with what felt like cold paper. "And you can open your eyes now."

Your looked up blearily at Zim, standing over you and holding a water cup. "Thanks, Zim," you said, sitting up shakily and drinking from it. A river of your cum immediately gushed out of your pussy onto the cushioned table. "Oh jeez." Normally you would be freaked out by ruining someone else's furniture, but right now your whole body tingled with warmth and a pleasant downy sensation that, if you had to describe it, was like being wrapped in a big fluffy bathrobe. "Whoops."

"Don't worry about it," Zim said with a wave of his hand. "I was going to replace that table anyway, after you laid down on it with your human germs." You hid a sheepish smile behind your cup. "More importantly, did you enjoy yourself?"

"Yes!" you exclaimed. "That was-- That was the best sex of my life! I just--" You looked at Zim's still very bright and swollen tentacular erection. "You didn't finish, did you?"

"I did not," Zim said matter-of-factly.

"Gimme a bit and then we can try again," you said, peppily. "Gimme juuuust a second after I finish this water and then it'll be round 2."

"Have two more cups. And I doubt this is advisable--"

"Oh, don't worry. I've fucked myself harder and more times merely _imagining_  I was with an alien. You're actually here, so that'll make things a lot easier," you quipped.

Zim looked unconvinced. "If you say so."

* * *

 

And that's how you ended up with Zim inside you for the second time. But now it was you on top, sitting on him, both of you sitting on the table, you maneuvering his dick into your hole, and pushing your tits in his face. He tried very hard to ignore them.

"Feels good, huh?" You grasped his head with your hands and gently tilted his face upwards, before dropping your hips down again onto his cock. Having your insides pushed aside again made you shiver. Everything was more sensitive the second time, to the point where you couldn't even touch your clit yet.

Zim remained quiet-- The way his teeth were gritted and his breath was frayed, he was clearly trying to avoid moaning. "It's OK," you reassured him. "You heard me scream like an animal! Moaning a bit is fine. In fact, it's cute."

"I despise that word, _cute_ \-- Ah!" You'd quickly pulled yourself upwards, thigh muscles clenching rapidly, then slammed back down again, maintaining a steady pace. You were going slower than the first time, but it seemed like slower, more torturous attention was what Zim's cock needed. In fact, he'd already begun to twitch and gasp a bit, losing control over his composure.

"Nn-- Look how much of a bulge you're making." Your abdomen sported a huge lump in the middle, one that moved up and down with every thrust. Zim whined softly in acknowledgement, then leaned forward, his forehead, slick and cool with sweat, touching yours.

"Human, I think I am about to-- To 'cum,'" Zim murmured faintly.

"What's gonna happen?"

"I will release a fluid similar in consistency to human semen. I may also-- I may also make an embarrassing noise, or an embarrassing face." Zim looked askance upon saying this. "I would prefer if you didn't look, but you can if you want."

"D-Do you lay eggs?" you asked, breathlessly.

Zim grimaced. "Yes. But it is a- An alternate, rarer, form of ejaculation. More difficult, but still possible."

"Well, what are you waiting for?" You squeaked out another moan as you sank deep onto his cock. God, the base was thick. You wondered how he could store all of this inside his tiny body. Zim didn't respond, so you continued, "You wanted to study how humans incubate alien eggs, right? Might as well get a fresh sample! Fresh is better than frozen, right?"

"There are already-- I've already put eggs inside you," Zim explained.

"Fill me up with more!" you exclaimed, like a proper slut.

"I-- I don't think you'd be able to handle that. Irken eggs are large when ready to hatch."

" _Hatch?!_ "

"Oh, I don't think these will hatch. But-- Can we talk about this later? I'm about to-- I think I will--" With this, Zim's hips began thrusting erratically, his lower body straining as he launched your combined weight in frantic bursts. You steadied your knees and maintained the pace, even though his legs thrashed against you. "Faster! Go faster! I'm about to-- About to cum!"

As he shouted, you felt something hot shoot up into you deep inside. Zim grasped your arms, nails digging trails into your skin, and when he breathed again it was hoarsely, taking big gulps of air. You felt his cum inside trickling down your thighs, and even though you hadn't cum a second time yourself, you were filled with an inexplicable warm and intimate sensation.

You watched Zim's face keenly, the knot in his expression slowly unraveling. "You done?"

"I… Have finished!" Zim shouted, then slumped over exhausted. His cock slipped out of you, coated in white foamy fluid. More of his and your intermingled fluids dripped out onto the table. "And now," Zim groaned, wriggling out from under you, "it is time to finish what you came here for. The experiment."

"Aw, you're not going to let me hold you for a bit?" You lay down. Zim hopped onto the floor, then stooped to pick up his clipboard.

"Holding may happen... afterwards. But right now I'm going to need you to push out those eggs." Zim turned to face you. "Once they're ready, Irken eggs release a combination dilating and numbing chemical that causes your sphincters to relax. Pushing them out should be easy."

You looked down at your belly. The big bulge from earlier was still there. "This is all from the eggs?" you asked, incredulous.

"They're just firm sacs of goo. It is highly unlikely that you and I are mutually fertile," Zim added.

"That's crazy, still. Being filled up so much by your... Alien eggs..." You rubbed your thighs against each other. "It's nice."

Zim sighed. "I will never understand humans."

A sudden twinge of discomfort bubbled across your abdomen and you gasped. "I think it's starting," you hissed through gritted teeth.

"Take it slow," Zim recommended. "Bend your legs at the knee and-- Here." Zim pressed a hidden button on the table's underside and it began to dip in the middle, elevating your back. You had no idea what that odd, twisting feeling was, but you were pretty sure that was your cervix dilating. And then the squeezing began.

"Zim, I think Irken pussies are-- Are looser than human ones," you grunted. Your pussy felt exceptionally stretched out. "I think this one got stuck," you whined.

"Take a moment to breathe, then try again," Zim said with uncharacteristic gentleness. You liked that tone of voice. You wished you could get lost in it. And so you did, ignoring your discomfort, and clamped down. After a few seconds, the egg popped out of you with a slick, wet sound, the rolling sensation causing a ripple of pleasure through your hole. You took several deep breaths, before seizing upon another egg, which followed right after. Zim scooped up both, placing them in a pre-labeled specimen box.

"Three more to go," Zim said. You were already halfway through the third, and with some concentrated effort that one slid through you with only minor trouble. Somehow, your body was getting off on this. Which was strange, because beyond the premise, this whole experience had nothing in common with your fantasies of alien impregnation. You hadn’t expected it to feel so tight, so… Lumpy. Yet the way the eggs rubbed against your walls, the way they plopped out, with heat and mass, the way they made you extremely full one second and then achingly hollow the next-- That actually felt pretty good.

With one last push, another egg popped out of your opening. "There's... One more, right?" You shut your eyes and clamped down, pushing with all your might.

"If it's stuck I can get it out," Zim offered.

"No, it's OK, it--" You smiled at him weakly. "It, uh. It feels good. To squeeze them out."

Zim blinked at you.

"Yeah, that's something for your clipboard. Ah." The last egg slid out. You threw your head back in relief. "Done. Now can we cuddle? Wait. What time is it?"

"5:34pm."

"Ah, so I have around two hours before my phone explodes." Zim didn't even react to this strange comment. "Come here, Zim!"

Zim went over to the sink to get himself some water, and cautiously approached the table where you lay. “I do not do _cuddles_.” He practically spat the word. “But I SUPPOSE…. I can lay alongside you for a bit. And of course, the compensation I promised will be on its way before you depart.”

“Say, Zim,” you butted in, “Would you be open to doing this another time?”

“I have all the data I will need,” Zim replied.

“I didn’t mean-- I didn’t mean the egg stuff. I meant, uh. Fucking.” Zim stared at you. You could feel yourself withering a little under his gaze. “I mean, it was fun for me, it looked like it was fun for you……..” You trailed off.

“Perhaps,” Zim said, as he hoisted himself up by your side.

“Well, you already fulfilled my dream tonight, so that’s already more than I can ask,” you said, tentatively putting an arm around Zim. He didn’t shrug it off or cut it off, which you took as a good sign. “I just thought that-- Aw, darn. Dammit. I’m not going to be around here for long. I don’t live here.”

Zim looked up at you slightly. “That is not a problem for Zim. I possess capable spacecraft. Flying around the world is not difficult in the slightest.”

“Oh, DUH,” you said, smacking your forehead. “You’re an alien.”

“That I am,” Zim said, smiling. “Give me that exploding phone of yours. I will punch in my number to contact. Whenever you would like to have… Intercourse!… Let me know.”

“Sounds good,” you said, and yawned, leaning over to grab your phone. This would all hit you later, you realized, and you would be on cloud nine for days, bragging to your friend-host until they were sick of it that you’d finally found an alien to fuck. But right now, all you could think about was…

Zim leaning on your shoulder. What?! You tried not to jump and shake him off. “I’m already going to be taking a full-body bath,” he explained, sounding resigned. “And your skin is warm.. It gives off such comforting heat.”

“Yours does too,” you said, and leaned back.

 

**Author's Note:**

> Merry Christmas, my dear! You know who you are <33


End file.
